1. Field of the Invention
This invention relates to the conversion of glycolonitrile to iminodiacetonitrile.
2. Description of the Prior Art
Numerous methods for preparing iminodiacetonitrile (IDAN) are disclosed in the prior art. For example, U.S. Pat. No. 2,511,487 to Thompson teaches reacting aminoacetonitrile with formaldehyde cyanhydrin at a temperature of about 50.degree. C. to 150.degree. C. in the absence of alkali.
U.S. Pat. No. 2,794,044 to Miller discloses reacting ammonia, formaldehyde and hydrogen cyanide in a molar ratio of 2:3:3 at a pH of 5.5 to 6.5 and a temperature of from about 0.degree. C. to 50.degree. C. for 10-24 hours.
U.S. Pat. No. 3,167,580 to Saunders, et. al. discloses reacting hydrogen cyanide, ammonia and formaldehyde while critically controlling the mixing of the reactants, the mole ratio of each of the reactants, the temperature and pH of the reaction, and the residence time of the reactants.
U.S. Pat. No. 3,412,137 to Stutts discloses preparing IDAN by reacting hexamethylenetetramine with about 6 molar equivalents of hydrogen cyanide in a buffered aqueous medium at a pH of from about 5 to 6.5 and a temperature of between about 0.degree. and 75.degree. C.
U.S. Pat. No. 4,661,614 to Most et. al. discloses preparing IDAN by reacting formaldehyde, hydrogen cyanide and a source of ammonia under substantially stoichiometric conditions at a temperature between about 30.degree. C. and 65.degree. C. and a pH between about 1.5 and 5.5.
However, each of the foregoing processes suffers from various drawbacks, such as the added burden of forming complex starting reactants, poor yield, critical reaction conditions, etc.